Infrared (IR) emission sources are useful for a variety of applications. IR emission sources are commonly used for both military and law enforcement purposes. Historical methods of emitting IR radiation for marking purposes such as ordnance targeting utilized a pouch containing chemicals that underwent an exothermic reaction on exposure to air to generate heat, and therefore infrared energy, for a period of time. These prior art systems suffered numerous drawbacks including single use, rapid chemical depletion and generation of chemical waste.
Chemical IR emitters have been replaced by IR emitting lamps. IR emitting lamps address several of the drawbacks of chemical emitters and are sufficient to be detected by optical equipment. Typical lamps that emit radiation in the near infrared (NIR) and far infrared (FIR) include a tungsten filament lamp, silicon carbide, or a xenon arc lamp. These lamps and other prior art IR emission sources suffer from low inherent efficiency, which is usually much less than 1 percent. Further, the tungsten filament lamp is susceptible to degradation through oxidation if operated in air and, like the xenon arc lamp, must be encased in a sealed vacuum chamber. Vacuum encasing drives up costs and decreases ruggedness. While the tungsten filament and xenon arc lamps have relatively fast rise times for IR emission, the tungsten filament has a slow decay time. Silicon carbide elements have slow rise and fall times. This hinders their use as identification or reference sources. Both tungsten and xenon arc lamps must also be filtered to achieve IR only emissions. Thus, xenon arc or silicon carbide lamps are optimally used in limited conditions such as where high emission sources are required. However, for applications where high IR emission density is not required or where only low power is available, the traditional lamp sources are not optimal.
Thus, there exists a need for a low power, high efficiency infrared radiation emitter.